Summary NEW AND IMPROVED! Revision 4 has modified outlets which direct air flow in a more downward direction, and less toward the nozzles. Also, STEP & IGES file formats (R4) are now posted. Made to fit a third 40mm fan for active cooling. The reason I designed this is because I wanted to get air all around the print. Having air coming from just the front was not working well for my needs. Check out some great before and after pictures here: http://www.thingiverse.com/make:75635 This design hugs a little closer to the extruder carriage than some other versions. This keeps it away from the front door hinge bolts! Helpful for PLA and ABS prints. Find the NEW Flash Forge version here: http://www.thingiverse.com/thing:259688 Instructions This thing is designed to print at 0.2 layer height, 2 shells, and 15% fill, no raft or support. I had a little trouble with bridging over the ducts. My solution was to turn off bridging and change the solid layer angle to 90 degrees. Be sure to clean out any "spaghetti" in the air ways. The chrome fan guards need to be removed. The fan bolts are M3-10.